STOCKHOLM, Sweden—Widespread pain following whiplash is rare and tends to occur soon after car accidents, according to a study in the Arthritis Care & Research. ¹

Most at risk for widespread pain are individuals with whiplash who report early symptoms of depression and those with severe neck injury, report researchers led by Lena M. Holm, BS, PhD, of the Karolinska Instituot, in Stockholm, Sweden.

"Further large studies are needed to determine the influence of preinjury and injury-related conditions to make conclusions about causal relations," the study authors conclude.

Patients began with localized pain

The researchers identified a subgroup of patients (n = 266) with only localized head/neck/back pain from a large prospective cohort of injury claimants who reported whiplash-associated disorder following the motor vehicle collision (N = 7462). Participants responded to one or more follow-up questionnaires mailed at 6 weeks and 4, 6, and 12 months after the car accident. Widespread pain was defined as having nine or more painful areas, including posterior neck, at any of these times. Researchers assessed depressive symptoms via the Center for Epidemiological Studies Depression Scale and pain intensity via a visual analog scale (VAS).

Overall, 21% of the 266 patients had widespread pain over the 1-year follow-up. Widespread pain tended to occur early after sustaining the injury. Specifically, 63% experienced the onset of pain before the first follow-up visit, which occurred a mean of 52 days after the accident (range 36 to 133 days). Another 20% of individuals went on to develop widespread pain by the second follow-up visit (mean 117 days, range 77 to 179). Widespread pain rarely continued over the entire 12 months of follow-up, the study showed.

Depressive symptoms triple risk for widespread pain

People who had depressive symptoms were more than three times as likely to develop widespread pain as their nondepressed counterparts. Those individuals with high pain intensity as assessed by the VAS (55–100) were also more than three times as likely to develop widespread pain following whiplash, the study showed. Study participants reporting >e;3 pain-associated symptoms were 90% more likely to develop widespread pain and those who reported four or five painful body areas were 2.6 times as likely to develop widespread pain.

"Subjects with whiplash-associated disorders who report early depressive symptoms, high neck pain intensity, many symptoms, and greater initial spread of pain are at higher risk for developing widespread pain after a motor vehicle collision," the study authors concluded.

"There are a lot of studies that find that a lot of people who develop whiplash pain are healthy at the time of injury and that specific demographic populations are more likely to get whiplash such as women and older people and these populations are more likely to have  more chronic symptoms once they are injured," said Brian Stemper, PhD, an assistant professor in the department of neurosurgery at the Medical College of Wisconsin in Milwaukee.
 
"I don't know what role mental health will play, but for clinicians treating patients with whiplash, the knowledge of the type of people more likely to be injured would be beneficial," he told CIAOMed. "Clinicians, in general, should look for those populations more likely to be injured including older individuals, those with preexisting spinal degeneration or women."
 
Dr. Stemper recently developed a mathematical model of the head and cervical spine that may help prevent whiplash. The model can be studied under simulated rear-end collision conditions. It provides quantifiable data on soft tissue distortions in humans. The model determined that auto head restraints positioned less than 2.4 inches (6 cm) from the back of the head kept ligament stretch within the physiologic range, meaning that no whiplash injury would occur. If the restraint distance increased beyond 2.4 inches,  whiplash injury will be more likely to occur. 
 
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Reference

1. Holm LM, Carroll LJ, Cassidy D, et al. Widespread pain following whiplash-associated disorders: incidence, course and risk factors. Arthritis Care Res. 2006;55:935-945.